Hi Scott,
thanks! It was mainly for the idea of making a tall BIB like I've got already, but with a small bend at the bottom to stop them going through the roof! Mainly so i can have the driver around the .434 point of the line length and also engage the ceiling better.
Does reducing the line length, reduce the load on the driver itself (not having to go so low therefore making the driver work less) or is it a case of the driver going there anyway and enhanceing what its giving out?
Cheers Stroop
thanks! It was mainly for the idea of making a tall BIB like I've got already, but with a small bend at the bottom to stop them going through the roof! Mainly so i can have the driver around the .434 point of the line length and also engage the ceiling better.
Does reducing the line length, reduce the load on the driver itself (not having to go so low therefore making the driver work less) or is it a case of the driver going there anyway and enhanceing what its giving out?
Cheers Stroop
It's the line that produces the grunt below 50Hz -Fs in the FE168ESigma is 51Hz if memory serves. Actually, in terms of driver excursion, there won't be much in it between a line 120in long and one 140in long. The longer line will just give another 10Hz extension, at the price of a touch more ripple, though in-room this latter is unlikely to be audible. The folded cabinets should actually filter some of the unwanted higher energy out compared with a straight version (higher frequencies hate bends), and will need less damping as a result.
Exact sizing for BIB 168EZ
I am wanting to get on and order materials now, but it is taking me ages to find out the exact info I need! Too much fun to be had reading threads and not enough doing...
Can someone please help me to work out actual dims for the enclosure?
I am decided on FE168E Sigs and I have looked at Zillas site for dims and charts. Can I just confirm that I am reading things correctly?
Sm = 74.25". Is this internal measurements? Does that mean I can make a narrow 7.42" box, 10" deep? External measurements roughly 9" x 11.5" and 64" high.
I would like to make them as narrow as poss when seen from the front and I have downloaded the measurements for the drivers. The basket dia is 5.63" which doesn't leave a lot of room. Is that OK? I am concerned about making the fronts too narrow and interferring with the drivers. The overall dia is 7.48"
Also - and here opens another big subject again...the front baffles. I like the look of them and have got some solid wood to make them from. Without stiring up a debate as to why they are there and if they adversly affect the sound, is it fairly easy to make some or are they really cleverly measured and accurately sculpted? If I make something that looks similar and mount the driver in it, am I really risking screwing up the sonic benefits of this design? I think they would look nice without them too, but I want to make these really special.
A practicla question re the build. It seemed that TC made cuts at 45deg and glued the edges together, which is quick and neat, but won't allow tweaking and adjusting amounts of stuffing etc. What do you guys do about this? How do you get to the closed area above the driver? Leave the bases off and screw them in later?
I have also read about making the internals in adifferent material to the outer. Why is this? What about the back?
Any suggestions welcome. I'm keen to learn, just point me to the right place
Martin
I am wanting to get on and order materials now, but it is taking me ages to find out the exact info I need! Too much fun to be had reading threads and not enough doing...
Can someone please help me to work out actual dims for the enclosure?
I am decided on FE168E Sigs and I have looked at Zillas site for dims and charts. Can I just confirm that I am reading things correctly?
Sm = 74.25". Is this internal measurements? Does that mean I can make a narrow 7.42" box, 10" deep? External measurements roughly 9" x 11.5" and 64" high.
I would like to make them as narrow as poss when seen from the front and I have downloaded the measurements for the drivers. The basket dia is 5.63" which doesn't leave a lot of room. Is that OK? I am concerned about making the fronts too narrow and interferring with the drivers. The overall dia is 7.48"
Also - and here opens another big subject again...the front baffles. I like the look of them and have got some solid wood to make them from. Without stiring up a debate as to why they are there and if they adversly affect the sound, is it fairly easy to make some or are they really cleverly measured and accurately sculpted? If I make something that looks similar and mount the driver in it, am I really risking screwing up the sonic benefits of this design? I think they would look nice without them too, but I want to make these really special.
A practicla question re the build. It seemed that TC made cuts at 45deg and glued the edges together, which is quick and neat, but won't allow tweaking and adjusting amounts of stuffing etc. What do you guys do about this? How do you get to the closed area above the driver? Leave the bases off and screw them in later?
I have also read about making the internals in adifferent material to the outer. Why is this? What about the back?
Any suggestions welcome. I'm keen to learn, just point me to the right place
Martin
How much of an experimenter are you-- as compared to a furniture
lover for example?
If I were doing a lot of tweaking I'd make a removable side.
Now to hold the side on would be screws and the edges all run with a bead of clear bathtub caulk. There's also some removable weatherstrip
material that comes in a caulk gun which is the glue that is that
bit which just rolls off when the flyer is removed from a magazine page.
I think you can search here under the word goo to find the
reference. Anyway it's some stuff that's available at the home store.
That bit about the tub sealant caulk I've used myself to good effect.
An MLTL and a BIB I have are both stuck together that way-- no screws.
After being clamped it doesn't break loose unless forced with a thin blade and is then removable.
Not really furniture style but the clear caulk is not obtrusive and can
be trimmed or rolled off with the finger like rubber cement where there is squeeze out.
lover for example?
If I were doing a lot of tweaking I'd make a removable side.
Now to hold the side on would be screws and the edges all run with a bead of clear bathtub caulk. There's also some removable weatherstrip
material that comes in a caulk gun which is the glue that is that
bit which just rolls off when the flyer is removed from a magazine page.
I think you can search here under the word goo to find the
reference. Anyway it's some stuff that's available at the home store.
That bit about the tub sealant caulk I've used myself to good effect.
An MLTL and a BIB I have are both stuck together that way-- no screws.
After being clamped it doesn't break loose unless forced with a thin blade and is then removable.
Not really furniture style but the clear caulk is not obtrusive and can
be trimmed or rolled off with the finger like rubber cement where there is squeeze out.
I try to avoid giving all the exact dimensions now because of severely limited time, and all the information needed is on this thread. However, it's v. long, and not the easiest to search, so:
All dimensions are internal. WxD ratio wants to be 1:1.4142 to preserve the flare around the base. Try not to deviate from this if possible. So internally 7.25in wide x 10.25in deep (always round up to the nearest sensible figure). If you're using 0.75in material, that will make for a box 8.75in wide x 12.5in deep.
The FE168ESigma can handle a slightly longer line than I suggested originally on the Zilla pages. I keep meaning to get the revision to Jeff. Increase the line length to 138in (70in tall cabinet externally) with a Zdriver of 27.75in from the internal sealed end.
Recently I've adopted GM's advice re damping materials. Junk the stuffing & instead, line the front of the internal sloping baffle, and one side-wall, from the top to just below the driver. Also, line the internal base of the enclosure. Stiff acoustic fiberglass is apparantly best, but tricky to get hold of in the UK, so self-adhesive bitumen damping sheets, which you can get hold of from car accessory / component shops (it's used for damping internal panels) is a good substitute.
The idea behind the different materials is to deliberately use something lossier for the internal baffle, base, and possibly the rear wall -something like chipboard (particleboard) should do for an FR driver, with birch ply for the rest.
All dimensions are internal. WxD ratio wants to be 1:1.4142 to preserve the flare around the base. Try not to deviate from this if possible. So internally 7.25in wide x 10.25in deep (always round up to the nearest sensible figure). If you're using 0.75in material, that will make for a box 8.75in wide x 12.5in deep.
The FE168ESigma can handle a slightly longer line than I suggested originally on the Zilla pages. I keep meaning to get the revision to Jeff. Increase the line length to 138in (70in tall cabinet externally) with a Zdriver of 27.75in from the internal sealed end.
Recently I've adopted GM's advice re damping materials. Junk the stuffing & instead, line the front of the internal sloping baffle, and one side-wall, from the top to just below the driver. Also, line the internal base of the enclosure. Stiff acoustic fiberglass is apparantly best, but tricky to get hold of in the UK, so self-adhesive bitumen damping sheets, which you can get hold of from car accessory / component shops (it's used for damping internal panels) is a good substitute.
The idea behind the different materials is to deliberately use something lossier for the internal baffle, base, and possibly the rear wall -something like chipboard (particleboard) should do for an FR driver, with birch ply for the rest.
Scott,
I have been out of touch for a few months due to a family loss and have just read your post regarding stuffing. If you can direct me to the initial post # that determined the stuffing change I would appreciate it.
I have not been happy with the cork lining of the front internal baffle and intended to re-do all stuffing so I may as well start with this configuration.
As a point of clarification, I assume that the "side wall to be lined from the top to just below the driver" is in the front cavity adjacent to the driver? Does the linning on the front of the internal baffle also stop just below the driver or does it extend the full length of the baffle?
Have you also abandoned the linning just below the mouth of the horn?
Ray
I have been out of touch for a few months due to a family loss and have just read your post regarding stuffing. If you can direct me to the initial post # that determined the stuffing change I would appreciate it.
I have not been happy with the cork lining of the front internal baffle and intended to re-do all stuffing so I may as well start with this configuration.
As a point of clarification, I assume that the "side wall to be lined from the top to just below the driver" is in the front cavity adjacent to the driver? Does the linning on the front of the internal baffle also stop just below the driver or does it extend the full length of the baffle?
Have you also abandoned the linning just below the mouth of the horn?
Ray
Since I have been following almost all postings regarding BIBs for the Fostex FE168E Sigma driver, let me chime in and summarise what Scott had said in Nov. last:
Driver : FE168E Sigma
Line Length : 140 inches
Zdriver : 29.25 inches
Sm : 74.25in^2
I suggest having a look at the following posts: 1760 to 1769, 1791 and 1792.
Optimal WxD can be found out from GM's Excel sheet.
Sorry to hear that Ray.
Not sure -it's what GM usually suggests re TQWT and often ML designs as well I believe (correct me if I'm wrong though Greg). Try running an internal thread search with GM and lining as tags.
Yes, driver cavity side of the line only, lined on one wall and on the front of the internal sloping baffle to just below the driver height, + the internal base. That should do it. The cork was useful on my original MDF cabinets & I still stand by it for those, though I hasten to add it's an addition to, rather than a replacement for the stuffing and / or heavier lining. Lining the top, around the terminus can be useful. More of a suck-it-and-see though, depending on cabinet / driver / room. Last thing to try I'd say.
Edit to typo in previous post: Zdriver 29.25in should give the best response with this driver / cabinet combination. Sorry for any confusion -I was doing a couple of things at once & ended up citing the zdriver for a different unit.
Cheers
Scott
Not sure -it's what GM usually suggests re TQWT and often ML designs as well I believe (correct me if I'm wrong though Greg). Try running an internal thread search with GM and lining as tags.
Yes, driver cavity side of the line only, lined on one wall and on the front of the internal sloping baffle to just below the driver height, + the internal base. That should do it. The cork was useful on my original MDF cabinets & I still stand by it for those, though I hasten to add it's an addition to, rather than a replacement for the stuffing and / or heavier lining. Lining the top, around the terminus can be useful. More of a suck-it-and-see though, depending on cabinet / driver / room. Last thing to try I'd say.
Edit to typo in previous post: Zdriver 29.25in should give the best response with this driver / cabinet combination. Sorry for any confusion -I was doing a couple of things at once & ended up citing the zdriver for a different unit.
Cheers
Scott
Maybe I am just not as critical as most. In my experience, being a bit off (say plus or minus and inch) never seems to make an audible difference to me. If a Voigt Pipe is 60” rather than 59” I don’t think there will be an audible difference. If your build ends up at 72” tall rather than 70” it’s ok as far as I’m concerned. This is of course if you are a DIY hobbyist building for yourself, friends or family. If you are a manufacturer your tolerances need to be to spec.
There is an overall ‘goodness’ to BIBs that makes them tolerant of minor errors/modifications. Same with Voigt Pipes. I doubt any audible differences would be discernable comparing two BIBs using the same drivers where one is two inches shorter. Now that Scott’s modified and improved the dimensions for the newer 168 making it nearly 10” taller, then YES there would be a difference in sound. That doesn’t mean the shorter one is a bad design.
All of the BIBs are just designs. They are great starting points (and great ending points too!). If I had the ability to design BIBs properly like Scott and GM I would add a bit of bottom end bloom like I do with ported boxes. Ported boxes seem to need to be built to tighter tolerances compared to BIBs IMO. Certainly rounding to the nearest quarter inch I’m sure is perfectly fine.
But when I model ported boxes I take the recommended dimensions and play with them to build a mild bass hump – making a less than optimal box that’s warmer sounding with slightly less bass extension. That’s my choice as a speaker builder.
For anyone worried about an inch here or there on their BIB I’d say don’t sweat that detail. Just make it an inch bigger and leave it at that… or, just make it an inch smaller. Either way, you will end up with a great sounding speaker.
There is an overall ‘goodness’ to BIBs that makes them tolerant of minor errors/modifications. Same with Voigt Pipes. I doubt any audible differences would be discernable comparing two BIBs using the same drivers where one is two inches shorter. Now that Scott’s modified and improved the dimensions for the newer 168 making it nearly 10” taller, then YES there would be a difference in sound. That doesn’t mean the shorter one is a bad design.
All of the BIBs are just designs. They are great starting points (and great ending points too!). If I had the ability to design BIBs properly like Scott and GM I would add a bit of bottom end bloom like I do with ported boxes. Ported boxes seem to need to be built to tighter tolerances compared to BIBs IMO. Certainly rounding to the nearest quarter inch I’m sure is perfectly fine.
But when I model ported boxes I take the recommended dimensions and play with them to build a mild bass hump – making a less than optimal box that’s warmer sounding with slightly less bass extension. That’s my choice as a speaker builder.
For anyone worried about an inch here or there on their BIB I’d say don’t sweat that detail. Just make it an inch bigger and leave it at that… or, just make it an inch smaller. Either way, you will end up with a great sounding speaker.
Greets!
Yeah, folks look at sims or even measured responses and most give themselves way too much credit for their keen hearing acuity and the larger the Vb and/or lower the Fb(p), the less likely they are to hear low percentage differences. Even in our so called 'acute' hearing BW most folks can't tell squat, just look at how many believe B@#$ consumer systems are high SQ, or their DIY efforts that have grossly mis-aligned XOs, etc., though females typically do much better than males and why they should get the final 'say' WRT system voicing if there's a 'significant other'.
GM
Yeah, folks look at sims or even measured responses and most give themselves way too much credit for their keen hearing acuity and the larger the Vb and/or lower the Fb(p), the less likely they are to hear low percentage differences. Even in our so called 'acute' hearing BW most folks can't tell squat, just look at how many believe B@#$ consumer systems are high SQ, or their DIY efforts that have grossly mis-aligned XOs, etc., though females typically do much better than males and why they should get the final 'say' WRT system voicing if there's a 'significant other'.
GM
Variac,
I have tried mine both ways and corner placement is significantly better. Against the wall is OK but it is not acceptable after hearing them in the corner.
Scott,
Thanks. I will try the new stuffing in addition to the cork on one of the BIB's and the other W/O. I am also working on new deflectors.
Ray
I have tried mine both ways and corner placement is significantly better. Against the wall is OK but it is not acceptable after hearing them in the corner.
Scott,
Thanks. I will try the new stuffing in addition to the cork on one of the BIB's and the other W/O. I am also working on new deflectors.
Ray
Scott and Greg, let me ask you: when simming these boxes, how sensitive are they to the various dimensional parameters? Which parameters are most sensitive and which are least?
On Zilla's page there are two sets of dimensions for the FE126E/FE127E, both identical except for Sm (43^2 and 63^2 inches.) Are these two narrow sweet spots, or is it more of a continuum between them? Would anything between 43 and 63 square inches work well according to the sim?
-- Dave
On Zilla's page there are two sets of dimensions for the FE126E/FE127E, both identical except for Sm (43^2 and 63^2 inches.) Are these two narrow sweet spots, or is it more of a continuum between them? Would anything between 43 and 63 square inches work well according to the sim?
-- Dave